Yes, but it's a slim one after his thumping in Illinois last night. The polls predicted a 15 point victory for Romney; the Regular Guy had predicted a single-digit result; but the 12 point victory by Romney was pretty impressive. Here's the thread-the-needle road to victory for Santorum. I'd give this about a 2% chance at this point:
1. Win Louisiana on Saturday.
2. Gingrich drops out.
3. Win Wisconsin convincingly on April 3rd and do well enough in Maryland and DC to actually win the day in terms of delegates.
4. Win Pennsylvania on April 24th convincingly and win at least one other state, preferably New York. (The other states include Connecticut, Rhode Island, and Delaware, all of which are probably too liberal for Santorum. New York ironically might be the least liberal of those states.)
5. Be at least semi-viable going into May, when the calendar is more favorable, including contests in the South (NC, Arkansas, Kentucky, WV, Texas) and Midwest (Indiana, Nebraska).
6. Generate enough momentum to make a run at the big enchilada in early June.... California, a winner-take-all state.
I frankly expect the reverse to happen. Santorum will win Louisiana, and Gingrich will get out, but Romney will start picking up endorsements, including, I expect, from three of the following four men: Paul Ryan, Scott Walker, Tommy Thompson and Ron Johnson. And then Romney will win Wisconsin convincingly and the pressure will be on for Santorum to bow out. He may limp along to Pennsylvania, win his home state on April 24th (and nothing else), and then get out with a ringing final speech that will set him up for a future in the party.